Compilers should not miscompile. Our work addresses problems in developing peephole optimizations that perform local rewriting to improve the efficiency of LLVM code. These optimizations are individually difficult to get right, particularly in the presence of undefined behavior; taken together they represent a persistent source of bugs. This paper presents Alive, a domain-specific language for writing optimizations and for automatically either proving them correct or else generating counterexamples. Furthermore, Alive can be automatically translated into C++ code that is suitable for inclusion in an LLVM optimization pass. Alive is based on an attempt to balance usability and formal methods; for example, it captures–but largely hides–the detailed semantics of three different kinds of undefined behavior in LLVM. We have translated more than 300 LLVM optimizations into Alive and, in the process, found that eight of them were wrong.
Mon 15 JunDisplayed time zone: Tijuana, Baja California change
09:00 - 11:00 | Distinguished PapersResearch Papers at PLDI Main BLUE (Portland 254-255) Chair(s): Steve Blackburn Australian National University | ||
09:00 15mDay opening | Opening and Welcome Research Papers | ||
09:15 25mTalk | Automatically Improving Accuracy for Floating Point Expressions Research Papers Pavel Panchekha University of Washington, Alex Sanchez-Stern University of Washington, James R. Wilcox University of Washington, Zachary Tatlock University of Washington, Seattle Media Attached | ||
09:40 25mTalk | Diagnosing Type Errors with Class Research Papers Danfeng Zhang Cornell University, Andrew Myers , Dimitrios Vytiniotis Microsoft Research, Cambridge, Simon Peyton Jones Microsoft Research, Cambridge Media Attached | ||
10:05 25mTalk | Provably Correct Peephole Optimizations with Alive Research Papers Nuno P. Lopes Microsoft Research, David Menendez Rutgers University, Santosh Nagarakatte Rutgers University, John Regehr University of Utah Pre-print Media Attached | ||
10:30 20mTalk | One Minute Madness Research Papers |